It airs every Monday through Friday at 9:15 p.m. (8:15 p.m. BST) (it airs every Monday and Tuesday night for the first 4~5 weeks because the female lead is injured). So now there are only two episodes online, but after 5 weeks it should be released five episodes a week, after all, Korean dramas are filmed and broadcasted as they go, so you have to wait until the female lead is healed.